Does it detect the position reliably or is it worth also allowing manually specifying a line?

Does it detect the position reliably or is it worth also allowing manually specifying a line?

So far, it's detecting the position perfectly with my tests. The switching sometimes occurs +- 1 lines across fields so the detection is nessisary to account for this. I also tried it with a multi generation tape and it's able to detect the multiple phase issues at the switching points and correct those as well.

It doesn't work with PAL though, just NTSC. Some future work on it could likely be done to get it to work for PAL though.

Another future improvement would be to detect where the switch happens mid-line, maybe by looking at the chroma above and below and checking where the phase matches up. I've noticed a few artifacts when the phase switch happens mid-line, but it's not too noticeable. Currently the phase switch detection is only looking at the color burst phase.